This invention relates to current sensors and, more particularly, to an alternating current sensor employing parallel plates.
Current sensors, such as U.S. Pat. No, 5,066,904, entitled "Coaxial Current Sensors," by Bullock, issued Nov. 19, 1991, assigned to the assignee of the present invention and herein incorporated by reference, are known in the art. These sensors, although useful, suffer from some disadvantages including the need for a current shunt to help reduce the expense of the current sensor by reducing the number of ampere-turns in the active part of the current sensor while also obtaining an accurate measurement of the current. However, even the use of an accurate current shunt typically introduces some expense due to the current sensor materials, such as low temperature coefficient materials, the large number of coil "turns" in the sensing and feedback coils of the current shunt, as well as the manufacturing care required to fabricate the current sensor. Thus, a need exists for a current sensor that overcomes these problems. Moreover, high-power circuit breaker applications generally require current sensors having a high dynamic range and accuracy while maintaining a relatively low cost and size.